• 대한기계학회논문집A
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• 제30권11호
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• pp.1439-1446
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• 2006

The fatigue test of the fillet weldments was executed with different beveling angles and porosities. The beveling angles of $0^{\circ}$, $45^{\circ}$ and $55^{\circ}$ were compared with fatigue lives. After the fillet weldment failure, the porosities which found at the fractured surface were observed to account the effect on fatigue life. Finite element analysis was performed to correlate the fatigue strength and the sizes and the locations of porosities. The stress-strain field was severely affected by the length of notch and the sizes and locations of porosities. Based on the quantitative analysis of porosity effect, the total volume of porosities was a key factor for fatigue strength of the fillet weldment.

• 대한조선학회지
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• 제20권4호
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• pp.17-24
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• 1983

In this study, it was investigated the distribution of residual stress in the direction of loading between the root and toe the load fillet welds for thick steel plate. Residual stress distributions are measured by sectioning method which is one of stress-relaxation technique in welded joint, and analyzed by two dimensional finite element method on thermo-elasto-plastic theory under plane stress condition. These are compared the results of F.E.M analysis with the experimental result by stress-relaxation techniques. As a results, the following conclusion were obtained. (1) In the no penetration fillet welded joint specimen using mild steel plate with 25mm in thickness, the residual stress of loading direction near the root was about $10kg/mm^2$ tensile. (2) The tensile residual stress has been observed in fillet region of the fillet joint by F.E.M. analysis method. (3) The range of compressive residual stress distribution from the root was largest in the case of 5mm root penetration.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.274-278
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• 2004

This study investigates the fatigue characteristics of SM 490 A material specimens for the railway vehicle due to the welding type. The more stress ratio decreases, the more strength of fillet welded specimen decreases. At speciallly, when the stress ratio of TN(Plate with transverse fillet welded rib) specimens decreases 0.5, 0.1, and -0.1, the fatigue limit decreases unifomly. The strength of TN is higher than it of NCN in the compare of fillet welding type, but the strength of NCN(Non load-carrying cruciform fillet welded joint) is higher than it of CN(Load-carrying cruciform fillet welded joint), which these specimens have the rib in the both side. We analysis the strains on the weld positions of the TN specimens during the fatigue test for the investigation of crack initiation and crack growth. In the theses results, we could find the fatigue crack initiation point and time.

• 한국기계가공학회지
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• 제6권2호
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• pp.9-16
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• 2007

The fatigue test of the fillet weldments were executed with different groove angles and porosity. The groove angles of $90^{\circ}$, $45^{\circ}$ and $55^{\circ}$ were compared with fatigue lives. After the fillet weldment failure, the porosity which found at the fractured surface were observed to account the effect on fatigue life. Finite element analysis were performed to correlate the fatigue strength and the size & the location of porosity. The stress-strain field were severely affected by the length of notch and the size & location of porosity. Based on the quantitative analysis of porosity effect, the total volume of porosity was key factor for fatigue strength of the fillet weldment.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.917-922
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• 2003

In this paper, a high speed rotating arc sensor for automatic fillet welding is introduced. In order to track the welding seam, The high speed rotating arc sensor is used. The welding tip of a high speed rotating arc sensor rotates about 3000 rpm using DC motor. The rotating torch is driven by gear between welding torch body and wire guide. The welding current is measured by using the current sensor and rot at ing position sensor. To realize the welding seam tracking algorithm with accuracy, a software filter algorithm using the moving average method is applied to the measured welding current in the microprocessor. The welding mobile robot with two wheels and two sliders is developed for fillet welding. The welding mobile robot can control its traveling direction and turn itself around the corner. The effectiveness is proven through the experimental results conducted with varied fillet tracking patterns.

• Journal of Welding and Joining
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• 제13권3호
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• pp.116-124
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• 1995

This paper presents an analytical solution to predict the transient temperature distribution in fillet arc welding including the effect of molten metal. The solution is obtained by solving a transient three-dimensional heat conduction equation with convection boundary conditions on the surfaces of a plate, and mapping the infinite plate onto the fillet weld geometry with energy equation. The electric heat input on the fillet weld and on the infinite plate is assumed to have a combination of two bivariate Gaussian distribution. To check the validity of the solution. FCA welding experiments were performed under various welding conditions. The actual isotherms of the weldment cross-sections at various distances from the arc start point are compared with those of simulation result.

• Journal of Welding and Joining
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• 제21권3호
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• pp.46-50
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• 2003

The horizontal fillet joint is one of the most important weld joints in the shipbuilding industry. High-speed rotating arc welding, which can increase the leg length, is an effective way to improve the weld productivity and quality for the horizontal fillet welding. Based on the Taguchi method, the effects of welding parameters on bead characteristics - leg length, asymmetry, undercut, overlap - are investigated fur high-speed welding process. As a result, the adequate welding parameters are selected for the required leg length, symmetric bead and no undercut. Besides, considerably consistent leg length is observed for the horizontal fillet welding with gap variation up to 3mm.

• 한국CDE학회논문집
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• 제10권2호
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• pp.114-120
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• 2005

This paper presents a novel method for radius measurement of fillet regions of polygonal models by using optimum onhogonal planes. The objective function for finding an optimum onhogonal plane is designed based on the orthogonality between the normal vectors of the faces in a filet region and the plane that is to be found. Direct search methods are employed to solve the defined optimization problem since no explicit derivatives of the object function can be calculated. Once an optimum orthogonal plane is obtained, the intersection between the onhogonal plane and the faces of interest is calculated, and necessary point data in the fillet region for measuring radii are extracted by some manipulation. Then, the radius of the fillet region in question is measured by least squares fitting of a circle to the extracted point data. The proposed radius measuring method could eliminate the burden of defining a plane for radius measurement, and automatically find a necessary optimum orthogonal plane. It has an advantage in that it can measure fillet radii without prior complicated segmentation of fillet regions and explicit information of neighboring surfaces. The proposed method is demonstrated trough some mea-surement examples.

• Journal of Welding and Joining
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• 제29권4호
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• pp.67-72
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• 2011

The proportion of the welding in the production process of machinery, buildings and marine structures is increasing and the joining are mainly conducted by butt and fillet weld. In the case of fillet weld, the shape of structures is complicated depending on the constraint on the geometry of the structures, therefore, the full penetration is mostly difficult. Accordingly, it is necessary to establish safe and economical criteria of design of the structures through the strength based on the penetration state of the fillet weld. Patterns of fatigue failure in cruciform fillet weld jont appear in the form of the root, toe and mixed failure. In the case of toe and mixed failure, the fatigue strength is higher than root failure. Therefore, we have to make the enough depth of penetration or perform the welding work through improving the fatigue strength of cruciform joints in welded structures. So it is necessary to optimize the penetrated depth in the range of the possible mixed failure and find the way in the cost-effective design to lessen the amount of the welding work.

• 대한조선학회지
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• 제6권2호
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• pp.5-10
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• 1969

A stepped bar with seimi-circular stress relieving groove near the fillet was subjected by axial tension in a polarized light field. On the stress concentration factor, the effect of the ratios of the fillet radius, the distance between two relieving grooves and the groove radius to the breath of the narrower portion of the stepped bar have been investigate. Observing the stress concentration in 48 models with various proportions, the conclusion arrived at were as follow: 1) If the fillet radius of the stepped bar is larger than half breadth of the narrower portion, the reduction of the stress concentrations can not be expected. 2) If the fillet radius is smaller than half breadth of the narrower portion of the stepped bar, the stress concentration can be droped to the reasonable range. 3) When the groove radius is larger than a quarter of the difference between the distance of two relieving grooves and the breadth of the stepped bar and smaller than a half of that, the stress concentration factors can have their possible minimum value. 4) When the sun of the breadth of the narrower portion of the stepped bar and twice of the relieving groove radius is smaller than the distance between two relieving grooves, minimum stress concentration can be obtained.